Kataoka et al. 2018 - Cadmium in chocolate and cocoa powder products in Japan
Kataoka and colleagues measured cadmium in 180 chocolate products and 140 cocoa powder products sold in Japan. The survey found broad product-level variation: chocolate products ranged from 0.00021 to 2.3 mg/kg Cd, while cocoa powder ranged from 0.015 to 1.8 mg/kg Cd. The paper is direct occurrence evidence for cadmium in chocolate and cocoa powder as sold in the Japanese retail market.
Key numbers
| Matrix | n | Cd range | Mean | Median | Maximum | Notes |
|---|---|---|---|---|---|---|
| Chocolate products, total | 180 | 0.00021-2.3 mg/kg | 0.20 mg/kg | 0.12 mg/kg | 2.3 mg/kg | Table 3; includes 140 dark, 35 milk, and 5 white chocolate products. |
| Dark chocolate | 140 | 0.025-2.3 mg/kg | 0.25 mg/kg | 0.15 mg/kg | 2.3 mg/kg | Table 3; eight of 180 total chocolate products exceeded the applicable EU maximum levels by the authors’ comparison. |
| Milk chocolate | 35 | 0.012-0.31 mg/kg | 0.043 mg/kg | 0.023 mg/kg | 0.31 mg/kg | Table 3. |
| White chocolate | 5 | 0.00021-0.0016 mg/kg | 0.00059 mg/kg | 0.00028 mg/kg | 0.0016 mg/kg | Table 3. |
| Cocoa powder products | 140 | 0.015-1.8 mg/kg | 0.32 mg/kg | 0.16 mg/kg | 1.8 mg/kg | Tables 3 and 4; 26 of 140 cocoa powder products exceeded the EU maximum level by the authors’ comparison. |
For chocolate products with labeled cocoa-solids content, the authors reported a weak positive association between cadmium concentration and cocoa-solids content. Table 5 grouped those 140 labeled products as <50%, 50% to <70%, 70% to <80%, and >=80% cocoa solids; the 70% to <80% group had the highest reported mean at 0.32 mg/kg Cd.
Methods (brief)
The study purchased 320 retail samples from April 2015 to August 2016, homogenized portions of each product, digested 0.5 g aliquots using nitric acid, hydrogen peroxide, and closed-vessel microwave digestion, and measured cadmium by ICP-MS. The stated limit of quantitation was 0.00005 mg/kg. Method validation used chocolate samples spiked at 0.005, 0.2, and 1.0 mg/kg Cd, with trueness of 101%-103%.
Implications
Certification: This is distribution-capable retail occurrence evidence for cadmium in chocolate products and summary-level occurrence evidence for cocoa powder products. Values are reported in mg/kg as sold and convert directly to ppb by multiplying by 1,000.
Courses: The paper is a clear example of why cocoa percentage matters for cadmium screening: white chocolate had very low Cd, while dark chocolate and cocoa powder carried the higher values.
App: Chocolate and cocoa powder should remain high-priority cadmium ingredients/matrices when the ingredient list indicates substantial cocoa solids or cocoa powder.
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Verification notes
The PDF title, byline, journal issue, DOI, sample counts, analytical method, and summary values were read from the source PDF. The source reports total cadmium only; it does not provide lead, arsenic, mercury, or cadmium speciation data. Brand names are not reproduced here; sample-level values are anonymized by sample number in the paper.
Page history
The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Description |
|---|---|---|
| 1476f44 | 2026-06-09 | ingest: cacic2019-hemp-heavy-metals fresh from MFK/June 9 |